The invention relates to the continuous monitoring of bonding force and of ultrasound amplitude during bonding processes with semi-automatic and fully automatic bonding machines.
Bonding is a mechanical connecting method which also simultaneously produces an electrical contact between the parts to be connected. This is achieved in a wire-bonding in that two parts that are initially mechanically non-identical (for example, a chip and a wire) are connected to one another by matching their surface structure.
During the manufacture of integrated circuits, chips are glued into a carrier member and are contacted to a frame with thin gold or aluminum wires. Since no equipment has been previously available for monitoring the semi-automatic and fully automatic bonding machines, serious adjustment deviations of the bonding machines frequently occur over the course of time. This causes a deterioration of the quality of the bond connections.
German published application No. 34 35 511 describes and shows an electrode for incorporation in resistance spot-welding machines. Wire strain gauges are applied to the electrode shank of this apparatus for measuring a bending moment during a milling. This, however, does not achieve a combined measured result in the sense of the present invention (continuous and simultaneous measurement of bonding force and ultrasound amplitude).
U.S. Pat. No. 3,857,279 describes the technique of measuring the 60 kHz ground frequency of bonding machines and its harmonies (multiples of the ground signal frequency).